Gameteophytes
often have have male parts called antheridia and female parts called archegonia.
These produce sperm and eggs respectively.

Members of these
non-vascular plant phyla are generally small and most must live somewhere damp.
Water is required for reproduction. However, many mosses practice a form
of hibernation where they dry out in times of drought and come back to life
after rainfall.

Bryophytes have
only limited ability to carry water around their tissues or stand upright.

Alternation
of generations is evident, gameteophyte is dominant.

(Sporophyte is
diploid generation and produces spores. Gameteophyte is haploid and produces
gametes (= sex cells = pollen and eggs in flowering plants, sperm and eggs in
most others).

As plants evolved from bryophytes to angiosperms we tend to see a transition
from dominant gameteophyte to dominant sporophyte.)

In non-vascular
plants, the sporophyte is small, always attached to the gameteophyte. Sporophyte
is completely dependant on the gametophyte for nutrition.

Spores are released
from the the sporophyte and these turn into a new haploid gametophyte.

"Old Man's
Cave", Ohio is an excellent place to see many members of this group.

Reproduction can
be sexual, (involving the production of sperm and eggs on attached, umbrella-like
antheridia and archegonia) or asexual through the vegatative production and
dispersal of "gemmae", which grow into new clones of the parent.

Liverworts are
the only bryophyte with membrane bound oil bodies in every cell. These
oils may have medicinal value, and liverworts are sometimes used in traditional
herbal medicines.

Riccia
can live both on land and floating on water. The shape of the plant changes
depends where it lives.

Liverworts never
have stomata, but they do have air chambers in their gametophytes which can
open and close.

Note the bushy
gameteophyte at the bottom with sporophyte consisting of a seta and a capsule
growing upwards.

Spores are released
from the capsule and grow into new male or female gameteophyte. In some species
the spores germinate to produce a simple microscopic filament called a protonema,
which gradually matures into the gameteophyte.

The “leaves” of
moss are not true leaves and are only one cell layer thick.

Sphagnum
is the only economically important moss. Gardeners use sphagnum to retain
moisture in soil (sphagnum has very thick cell walls which absorb water).

Specific
types of moss can be used to identity minerals in the soil. The Copper
moss grows on soil enriched with copper. Leucobryum (white pillow moss)
grows on soils enriched with calcium.

Mosses
are divided into 2 large groups- those with gametophytes that grow upwards
and don’t branch and those with gametophytes that spread over soil and do
branch.

Some species may
grow underwater (Java moss - Vesicularia).
Java moss is a common ornamental species in freshwater aquaria.

Dr. Fred Sack of
OSU uses moss to study how plants respond to gravity. His team works with the
protonema of the moss Ceratodon. They use the protonema form because
it grows easily on small agar plates and is easy to observe under a microscope.
Dr Sack and his team of graduate students have flown moss on 2 NASA space shuttles.
He flew moss on the space shuttle Columbia, which tragically broke up during
entry to the atmosphere. Fred’s moss was found in Texas and he was the
only biological researcher to collect data from the Columbia mission.
For more on this story see here
and here.

Some groups of
lycophytes have underground gametophytes that require mycorhizzae to live. These
gametophytes can live for many years.
Lycopodium spores contain votatile oils. These spores are used as flash
powder in old fashioned photography.

200 - 400 million
years ago, Lycophytes formed huge forests - important source of decomposing
plant material that was compressed and aged under layers of sediment until it
turned into coal.

Pteridophytes are
probably just ferns, based on sperm morphology and many molecular studies.
The text books haven’t kept up with the research.
Extremely common in greenhouses. Look for Psilotum
growing as a weed in many different pots in the OSU greenhouse (ask the staff
if you cannot find it).

Gametophytes are very similar to Lycopod gametophytes; they look like little
sub-terranian turds.